Summary of work: Manuscript for the the analysis of the NHANES-I twenty year follow-up is under revision. In collaboration with the Applied Physiology Section, formulae have been developed for the composition of percent body fat from anthropometric measurements. These data have been obtained on BLSA participants since the study was initiated. We now have adequate body composition data from Dual Energy X-rayAbsorptiometry studies which allow derivation of formulae for percent fat computation based upon multi-variate prediction equations on men and women. In collaboration with two scientists from the National Institute for Longevity Sciences in Nagoya, comprehensive analyses of the relation of anthropometric and metabolic variables is being performed. Body Mass Index and Percent Body Fat (from DEXA) as well as estimates of the pattern of fat distribution are being related to eight risk factors (systolic and diastolic blood pressures, fasting and two-hour post-glucose plasma glucose concentration, and four plasma lipid moieties) are being examined in younger and older men and women. Waist circumference has emerged as the dominant measure of fat distribution and percent body fat out-performs the BMI. The NHLBI "Evidence Report" on obesity was issued in July 1998 and provided single health cutpoints for the waist circumference measurements in men (102 cm) and in women (80 cm). No "grey zone" was defined although BMI range was divided six groups. We are therefore applying sophisticated statistical techniques to determine whether an intermediate zone (a "moderate danger" zone) for waist circumference can be quantified.